The present invention relates to a suspension system, and more particularly to an active suspension system that utilizes an incompressible fluid.
Conventional suspension systems isolate the vehicle frame or chassis from impacts and vibrations resulting from vehicle wheels traversing uneven terrain. Vehicle ride characteristics have complex dynamics. Excess vibration results in detrimental consequences.
Current passive suspension systems employ springs, struts, rubber elements, torsion bars, or the like to maintain a centered suspension. Perturbations from the norm initiates a harmonic motion that would continue indefinitely but for the addition of damping mechanisms such as shocks, or other hysterisis or coulomb damping devices. Current suspension technologies are defined in frequency domains with natural frequencies and damping coefficients to define the suspension characteristics. Such passive suspension systems offer a compromise between spring and dampening coefficients of fixed rates.
Current active suspension systems provide powered components which isolate the vehicle frame from vibrations induced by uneven terrain. In active vehicle suspension systems, actuators are provided to actively apply forces which counteract and balance forces applied to the chassis of the motor vehicle. Such active systems utilize relatively complicated control schemes to determine the amount of force which actuators should apply to the vehicle chassis to provide a smoother ride, such as schemes based on balancing the forces acting on the chassis and schemes based on supporting the vehicle chassis at a selected ride height. Active suspension systems may require relatively large power inputs to provide an actuator that is quick enough to compensate for impacts and vibrations which occur at desired traveling velocities over rough terrain. The power requirements for such fully active suspension systems are generally prohibitively demanding.
Accordingly, it is desirable to provide an active center seeking suspension system which responds rapidly while utilizing minimal power inputs and damping elements.